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Jing-Ling Chen

Publications and source records attributed to Jing-Ling Chen.

177 records · Page 10Linked to original sources
arXiv2003

Security of Quantum Key Distribution with entangled quNits

We consider a generalisation of Ekert's entanglement-based quantum cryptographic protocol where qubits are replaced by qu$N$its (i.e., N-dimensional systems). In order to study its robustness against optimal incoherent attacks, we derive the information gained by a potential eavesdropper during a cloning-based individual attack. In doing so, we generalize Cerf's formalism for cloning machines and establish the form of the most general cloning machine that respects all the symmetries of the problem. We obtain an upper bound on the error rate that guarantees the confidentiality of quNit generalisations of the Ekert's protocol for qubits.

quant-ph↗
arXiv2002

Clauser-Horne-Bell inequality for three three-dimensional systems

In this paper we show a Bell inequality of Clauser-Horne type for three three-dimensional systems (qutrits). Violation of the inequality by quantum mechanics is shown for the case in which each of the three observers measures two non-commuting observables, defined by the so called unbiased symmetric six port beamsplitters, on a maximally entangled state of three qutrits. The strength of the violation of the inequality agrees with the numerical results presented in Kaszlikowski et. al., quant-ph//0202019.

quant-ph↗
arXiv2001

Understanding Quantum Entanglement of Bipartite System Based on Bell Inequality

We present an alternative definition of quantum entanglement for bipartite system based on Bell inequality and operators' noncommutativity. A state is said to be entangled, if the maximum of CHSH expectation value $F_{\max}$ is obtain by noncommutative measures on each particle of the bipartite system; otherwise, the state is a disentangled state. A uniform measure quantifying the degree of entanglement for any state of the bipartite system is also proposed.

quant-ph↗
arXiv2001

Clauser-Horne inequality for qutrits

In this brief report we show the new Bell-Clauser-Horne inequality for two entangled three dimensional quantum systems (so called qutrits). This inequality is violated by a maximally entangled state of two qutrits observed via symmetric three input and three output port beamsplitter only if the amount of noise in the system equals ${11-6\sqrt3 \over 2}\approx 0.308$. This is in perfect agreement with the previous numerical calculations presented in Kaszlikowski {\it et. al.} Phys. Rev. Lett. {\bf 85}, 4418 (2000).

quant-ph↗
arXiv2001

Entangled qutrits violate local realism stronger than qubits - an analytical proof

In Kaszlikowski [Phys. Rev. Lett. {\bf 85}, 4418 (2000)], it has been shown numerically that the violation of local realism for two maximally entangled $N$-dimensional ($3 \leq N$) quantum objects is stronger than for two maximally entangled qubits and grows with $N$. In this paper we present the analytical proof of this fact for N=3.

quant-ph↗
arXiv2000

Quantum dynamical theory for squeezing the output of a Bose-Einstein condensate

A linear quantum dynamical theory for squeezing the output of the trapped Bose-Einstein condensate is presented with the Bogoliubov approximation. We observe that the non-classical properties, such as sub-Poisson distribution and quadrature squeezing effect, mutually oscillate between the quantum states of the applied optical field and the resulting atom laser beam with time. In particular, it is shown that an initially squeezed optical field will lead to squeezing in the outcoupled atomic beam at later times.

quant-ph↗
arXiv1998

Determine the parameter Bk of the K0-K0bar system by means of the precise Cabibbo-Kobayashi-Maskawa matrix elements

Taking use of the relation between weak CP phase and the other three mixing angles in Cabibbo-Kobayashi-Maskawa matrix postulated by us before, the uncertainty coming from the weak interaction can be reduced, furthermore, by means of the relation between the calculation result about mixing parameter epsilon from the box diagrams and the related experimental data in K0-K0bar system, the parameter Bk can be extracted. We take Vud, Vub and Vtb as inputs, when we let them vary in the ranges 0.9745<=Vud<=0.9760, 0.0018<=Vub<=0.0045 and 0.9991<=Vtb<=0.9993, we find the permitted window for Bk is 0.444<=Bk<=1.242. With the more precise measurment on the CKM matrix elements in the future, we can determine Bk more precisely.

hep-ph↗
arXiv1998

Shift Operators for XXX-Heisenberg Chain

The shift operators for XXX-Heisenberg chain are found. They are formed by local Yangian operators and the amplitutes of the eigenfunctions obeying Bethe ansatz for the Hamiltonian. The physical implication of the shift operators are also explained.

cond-mat↗
arXiv1998

A Possible Hidden Symmetry and Geometrical Source of the Phase in the CKM Matrix

Based on the present data, the three CKM angles may construct a spherical surface triangle whose area automatically provides a "holonomy" phase. By assuming this geometrical phase to be that in the CKM matrix determined by an unknown hidden symmetry, we compare the theoretical prediction on $ε$ with data and find they are consistent within error range. We also suggest restrictions for the Wolfenstein parameters explicitly, the agreement will be tested by more precise measurements in the future. At least we can claim that such geometrical phase should be part of the weak phase appearing in the CKM matrix, even not the whole.

hep-ph↗
arXiv1997

New Viewpoint to the Source of Weak CP Phase

The relation between CP-violation phase angle and the other three mixing angles in Cabibbo-Kobayashi-Maskawa matrix is postulated. This relation has a very definite geometry meaning. The numerical result coincides surprisingly with that extracting from the experiments. It can be further put to the more precise tests in the future.

hep-ph↗
arXiv1997

A Constraint on EHNS Parameters from Solar Neutrino Problem

We suppose that the solar neutrino problem is only due to the mechanism introduced by Ellis, Hagelin, Nanopoulos and Srednicki (EHNS), then a lower limit constraint on EHNS parameters is obtained. We find that gamma > 7.4 10^(-22)GeV if alpha < 2 gamma and alpha > 1.5 10^(-21)GeV if alpha > 2 gamma, this limit is consistent with the upper limits extract from the K0-K0bar system and can be detected in the future experiments.

hep-ph↗